Oceanographers and biologists on board the CSIRO research vessel RV Investigator were thrilled with their brief visit to Montague Island earlier this month.
The distinctive 94m-long, 6000-tonne vessel is Australia’s premier oceanic research vessel and this was its second visit to Montague Island in the past two years, as it visited the same time last year.
This latest 19-day voyage saw the RV Investigator travel from Brisbane all the way down to Montague Island before returning to Sydney. The vessel spent about nine hours taking samples off Narooma and the island on Sunday, September 17.
Among those on board was Professor Iain Suthers from the Sydney Institute of Marine Science (SIMS) at the University of New South Wales.
Scientists were examining the biological oceanography, including plankton, bioacoustics and whales, in the waters of NSW and out to 200km offshore, he said.
“”We were focussed on eddies of the East Australian Current to put biological characteristics on we can see on satellite imagery,” Dr Suthers said.
One of the highlights was finding a patch of larval lobster just off Jervis Bay on the way down to Montague Island, with 70 tiny juvenile lobster found, the largest ever sample collected anywhere in the world. Scientists suspect the warm core eddies are a nursery ground for the 12-month-old larvae.
“It’s important to convey how incredibly rare these animals are at this stage; so we are ignorant of their biology and why yields of lobster, and most other fisheries, vary from year to year,” Mr Suthers said.
“We just happened to be at the right place, at the right time – early evening, in the upper water column, and had a team of young student eyes to spot them in the contents of the trawl.
“Hence finding 70 in a one-hour trawl, filtering around 700,000 cubic metres of water, indicates that even when abundant, they are really sparse.”
But it was not all plain sailing with three strong weather fronts encountered on the three-week trip, and the visit to Montague was just squeezed in before the vessel had to get back to Sydney.
Dr Suthers said everyone on board was blown away by the number of humpback whales and common dolphins encountered off Montague Island, as well as large schools of blue mackerel identified on sonar that these marine mammals appeared to be feeding on.
Also on board was a researcher working with Dr Rob Harcourt from Macquarie University looking at the foraging habits of little penguins on Montague Island.
It will now take several more weeks to analyse the data and piece together the ecosystems of the coastline.
“It was quite exciting to see such a confluence of oceanography, plankton, fish, whales and dolphins,” he said. “The island is a great place to do our studies.”